Log in

View Full Version : 90 Civic ECU Light doesn't Turn ON


HCivicDX91
Jun 16, 2007, 05:06 PM
Hello
I have a 1990 Honda Civic DX HB and it won't crank over (Wont Start) I've Tried everything so that the ECU light would turn on I did the following to the car I Chance the ECU, Alternator, Distributer, Spark Plugs, Spark Plug Wires, and Starter and I still have no luck I then found out that there was no sparks in the spark plugs and I'm not sure if the car isn't well timed or if one of the wires from the ECU are broken
Please give me ideas on how to fix it
Thank You

TxGreaseMonkey
Jun 16, 2007, 05:29 PM
1. Test all under-dash and under-hood fuses with a test light or multimeter. Pay particular attention to the ACG (S) (ALT) 15 A fuse in the under-dash fuse box and the ECM Backup fuse in the under-hood fuse box. Here's how to properly test each fuse:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post252145

2. Check the ignition switch and harness.
3. Check the main relay.
4. Clean main ECM ground on the thermostat housing.
5. Read sections A and B in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563.html

Because the starter motor won't crank and the ECM light won't come on, the culprit is likely a fuse, ignition switch and harness, or main relay.

Handyman2007
Jan 26, 2013, 04:12 PM
One more thing... it could possible be a bad ground. Check the negative battery cable to the engine block AND the ground wire that goes from the engine to the firewall.